Embodiments of the disclosed technology include patterning a graphene sheet for biosensor and electronic applications using lithographic patterning techniques. More specifically, the present disclosure is directed towards the method of patterning a graphene sheet with a hard mask metal layer. The hard mask metal layer may include an inert metal, which may protect the graphene sheet from being contaminated or damaged during the patterning process.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for providing a temporary layer on a graphene sheet comprising: transferring a graphene sheet to a selected wafer; depositing a gold layer to a first surface of the graphene sheet by dipping the graphene sheet in a gold plating solution; patterning the graphene sheet by etching away areas of the gold layer and the graphene sheet corresponding to areas patterned in a photoresist layer using a lithography process; packaging the patterned graphene sheet and temporary protective portions of the gold layer not etched away during the patterning of the graphene sheet into a graphene-based device, wherein the packaging comprises epoxy curing; and removing, after packaging the graphene-based device, the temporary protective portions of gold layer by exposing the gold layer deposited to the surface of the graphene sheet to a non-acidic solution comprising potassium iodide.
2. The method of claim 1 , wherein the temporary protective portions of the gold layer are washed in the non-acidic solution comprising potassium iodide for a duration ranging from about 30 seconds to about 5 minutes.
3. The method of claim 1 , further comprising washing the graphene sheet with deionized water to remove any remaining particles or contaminants left on the patterned graphene sheet from the step of removing the gold layer.
4. The method of claim 1 , further comprising depositing a platinum layer on the selected wafer prior to packaging the graphene sheet.
5. The method of claim 4 , wherein the depositing the platinum layer comprises forming an electrode, wherein the electrode is electrically coupled to the graphene sheet.
6. A method for providing a temporary layer on a graphene sheet comprising: transferring a graphene sheet to a selected wafer; depositing a metal layer forming the temporary layer on the graphene sheet; patterning the graphene; packaging the patterned graphene sheet and the metal layer into a graphene-based device, wherein the packaging comprises epoxy curing; removing, after packaging the graphene-based device, the metal layer from the graphene sheet, wherein the metal layer comprises gold, ruthenium, silver, iridium; and wherein removing the metal layer comprises exposing the graphene sheet to a non-acidic solution.
7. The method of claim 6 , wherein the depositing the metal layer comprises applying an electron beam evaporation process.
8. The method of claim 6 , wherein the depositing the metal layer comprises applying a focused ion beam process, a filament evaporation process, a sputter deposition process, or an electrolysis process.
9. The method of claim 6 , wherein the removing the metal layer comprises washing the metal layer with a potassium iodide solution.
10. The method of claim 9 , wherein the washing the metal layer comprises washing the metal layer for a duration ranging from about 30 seconds to about 5 minutes.
11. The method of claim 10 , further comprising washing the graphene sheet with deionized water to remove from the graphene any remaining particles or contaminants left from step of removing the metal layer.
12. The method of claim 6 , further comprising depositing a platinum layer on the selected wafer prior to packaging the graphene sheet.
13. A bio-sensor chip comprising: a graphene-based device with a patterned graphene portion protected from contamination or damage during packaging and assembly of the graphene-based device by a temporary protective metal layer that is removed from the patterned graphene portion after the packaging and the assembly of the graphene-based device; and one or more bottom electrodes spaced apart and disposed directly under the patterned graphene portion; wherein the graphene-based device is manufactured according to the following process steps: transferring a graphene sheet to a selected wafer; depositing a gold layer to a first surface of the graphene sheet by dipping the graphene sheet in a gold plating solution; patterning the graphene sheet by etching away areas of the gold layer and the graphene sheet corresponding to areas patterned in a photoresist layer using a lithography process; packaging the patterned graphene sheet and portions of the gold layer not etched away during the pattering of the graphene sheet into a graphene-based device, wherein the packaging comprises epoxy curing; and removing, after packaging the graphene-based device, the gold layer by exposing the graphene sheet to a non-acidic solution.
14. The bio-sensor of claim 13 , wherein the depositing the gold layer comprises applying an electron beam evaporation process.
15. The bio-sensor of claim 13 , wherein the depositing the gold layer comprises applying a focused ion beam process, a filament evaporation process, a sputter deposition process, or an electrolysis process.
16. The bio-sensor of claim 13 , wherein the removing the gold layer comprises washing the gold layer with a potassium iodide solution.
17. The bio-sensor of claim 13 , wherein the graphene-based device is further manufactured by depositing a platinum layer on the selected wafer prior to packaging the graphene sheet.
18. The bio-sensor of claim 13 , wherein the portions of the temporary protective layer that were not etched away prior to patterning the graphene sheet remain deposited on the patterned graphene sheet while the graphene-based device is subjected to one or more assembly processes comprising wafer slicing.
19. The bio-sensor of claim 18 , wherein after the wafer slicing, the portions of the temporary protective layer that were not etched away prior to patterning the graphene sheet remain deposited on the patterned graphene sheet while the graphene-based device is subjected to one or more processes selected from wire bonding, encapsulation, and cleaning.
20. The bio-sensor of claim 18 , wherein after the wafer slicing, the portions of the temporary protective layer that were not etched away prior to patterning the graphene sheet remain deposited on the patterned graphene sheet to protect the graphene from damage during one or more high temperature treatments selected from oven baking and burn testing.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
June 14, 2017
July 6, 2021
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